Ford F-250



March, 22, 2007 AT 11:23 AM

2002 f-250 powerstroke, 90K, 7.3
when at an idle the engine 'pulses', the rpms go up and down and all lights inside and out pulse with the sound of the pulsing rpms. At higher speeds you can not tell if the engine is pulsing or if the rpms are fluctuating however the lights continue to pulse.
It is almost in a 1 second cadence, on-off-on-off.
Have a new fuel and air filter in place, no change. Thinking of moving to the fuel pump next. Any thoughts?

2 Answers



March, 22, 2007 AT 2:09 PM

Usually an engine that changes idle speeds needs the intake looked at. The lights are likly to be the regulator section of the alternator.



March, 24, 2007 AT 4:28 PM

To me it sounds like regulator in the alt. Is takeing a dump on you. The engine RPM will move up and down when the alt. Kicks on and off. The lights will go brite and dim when the battery's are a little low and the altenator is trying to charge them and the regulator can't handle it. Go to Auto zone they'll check it out for free!

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